Many types of self-contained applicators for liquids have been described in the prior art. The extremes may be said to be the pressurized aerosol can and the manually operable applicator combinations. Manually operable applicator combinations have been basically of two types: those that must be inverted so that the liquid contents flow by gravity through some kind of valving mechanism, and pump and dip tube type dispensers that are intended to be operated from an upright or nearly upright position.
An example of the gravity-feed valved applicator is given by U.S. Pat. No. 3,147,512 to Gleason, "Shoe Polish Dispenser."
Manually-actuated pump-container combinations that pump a liquid up from the bottom of a container through a dip tube and out a nozzle which ejects the liquid in the form of a spray or mist are well known. Such combinations are most frequently used for the application of such things as hair spray, colognes, cleaner, or weed killers.
U.S. Pat. No. 4,652,163 to Karlier et al., "Liquid Applicator with Scraper and Method of Use" discloses a gravity-flow type applicator. The applicator has a liquid container with an attached applicator, a detachable scrape overcap, and a separate protective cover. Transfer of liquid between the container and the applicator, which has a sponge on its outer surface, is regulated by a nozzle and spring valve assembly located within the container. The spring holds the nozzle against the inside of the neck of the container and seats the container. When force is applied to the applicator, the nozzle, which is located right under the applicator pad, is pushed back into the container, opening a channel between the nozzle and the neck opening of the container, allowing the liquid to flow out onto the applicator.
An applicator for liquids having a container, a foam applicator, and a ball valve dispensing means is disclosed by U.S. Pat. No. 3,192,553, to Schwartzman, "Dauber Having Spherical Valve Head." This applicator, whose main intended use is the application of shoe polish, has a hollowed tapered opening to the top of the container. A ball, which is seated on a carrier supported by a spring formed by helical coils, is located within and pressed into this opening. When pressure is applied against this ball, it is pushed backwards against the spring and into the container opening, allowing liquid to escape from the container around the ball valve and onto a sponge applicator which covers the container opening ball valve structure. Obviously, no liquid will escape the container unless the applicator device is inverted so that the liquid runs out the opened valve by gravity flow.
U.S. Pat. No. 4,091,966 to Laawe, "Squeeze Bottle Containing A powdered product and Operative Whether Upright or Inverted" discloses a flexible bottle from which powder can be ejected by squeezing the bottle, the powder first entering a U-shaped tube within the bottle and connected to the dispensing orifice. The tube has an opening at the bottom of the U, through which powder enters the tube when the bottle is upright, and an apparatus at one top of the U, through which powder enters the tube when the bottle is inverted.
The problem with existing manually operable applicator combinations having non-pressurized reservoirs is that, as stated before, the operating positions for the two main types are not only opposite but mutually exclusive. A gravity-feed device will not work in the upright position, nor will the traditional dip tube and manual pump work in the inverted position (since the inversion usually leaves the end of the dip tube above the surface of the fluid). This limits the method and direction of application of the fluid onto a surface and requires creative angling on the part of the user. Thus, a manually operable fluid applicator capable of applying a fluid in either the upright or inverted position would facilitate fluid application over a variety of orientations of surfaces. In addition, such a device should have some means of metering the flow of the fluid, a feature built-in to all pump-operated devices but missing from most gravity-feed devices.
When the fluid to be applied is intended for insect control, the advantages of a device capable of applying a neat strip of insect-killing or repelling solution to surfaces of different orientations become even greater.
To briefly summarize the current methods of killing insects: methods of introducing roach and ant, or other insect killers into an area range from the use of fumigators, which disperse the insecticide throughout the area and usually require the removal of foodstuffs from the area, to the application of insecticidal foams to selected areas, a method which is especially effective for cracks and crevices, but one that, when the foam is applied to exposed areas can leave an undesirable residue, to the placing of insect devices such as bait stations in an area.
Pressurized cans for the application of insecticides are frequently used to control insect populations, but there are times when it is desirable to be able to control placement of the insecticide exactly, with no possibility of drift.
Despite this variety of approaches to the problem of killing insects with various types of insecticides, no method or apparatus exists which allows direct and localized application of a liquid insecticide without the necessity of direct user contact with the insecticide to a selected area, whether that area be the bottom of a cabinet or the underside of a shelf. Such a method and apparatus would employ an applicator integrally connected to a container and would allow the user to apply the contents manually and with one hand. Such a method and apparatus would allow the user to stripe insect "barriers" across zones of expected insect travel for maximum effectiveness, stripes that would be invisible yet relatively long lasting, depending upon the formulation of the insecticide used.
Such a method and apparatus would avoid the need for the placing of a separate bait station in an area, but obviously, should not be used on an area that pets or children would be expected to eat from or lick.
Thus, it is an object of the present invention to provide an apparatus for applying a fluid that is self-contained, manually operable, and capable of applying in any orientation, metered amounts of the fluid, so long as enough fluid remains in the reservoir to enter the pumping mechanism.
It is a further object of the invention to provide such an apparatus adapted for use as an insecticide applicator and to describe a method of using such an apparatus for control of insect populations or for keeping insects from reaching an area.